It's written in the summary (yes, the summary, not the article) that it's an extension, not a plugin. There Is A Difference, You Know.

Only the old appearance was kept (and removed) as an option. The behaviour was changed long before the appearance was, and the options to modify it were added only immediately after the 3.0 release.

Actually, that doesn't restore the Fx 2 behaviour. With only this setting, the bar still searches titles, unlike Fx 2.

OMG, I made a mistake. The link for "options" that I posted is outdated. This one describes the current situation.

They've added options to return everything but the appearance to the Fx 2 behaviour. For that missing part, there's oldbar.

Mono does have implementations of non-standard .NET features, such as System.Windows.Forms. These might have patents. Tomboy (and most Mono apps written for use on Unix-like systems) don't use them, but that doesn't magically make their implementations disappear.

The FSF considers the QPL a free software licence, even if such distribution restrictions are not explicitly stated in their definition.

I actually my assignment late. Or it accidentally?

But the only Java VM installed on most Windows users' machines is the Oracle version. There's an extra distribution step, just like with the different versions and implementations of .NET.